Risk Of Relapse In Acute Myeloid Leukemia Research Articles

Molecular genetic and cytofluorimetric prognostic factors in the development of acute myeloid leukemia relapse in children after allogeneic hematopoietic stem cell transplantation

Relapse of acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains one of the main causes of reduced long-term survival. Modern methods for predicting the risk of AML relapse after allo-HSCT take into account the data on the pre-transplant level of minimal residual disease (MRD) determined by flow cytometry and molecular biological studies of recurrent genetic abnormalities, which are currently widespread in clinical practice. Recent studies of the expression of genes characteristic of leukemic stem cells (LSCs) have shown prognostic significance for children with AML in relation to treatment response and the risk of relapse. The study of LSC persistence in order to predict the risk of recurrence after allo-HSCT in children with AML in addition to standard MRD detection methods may be of great importance. The aim of the work was to evaluate the impact of MRD status, both using classic methods and taking into account the genes characteristic of LSC, on the results of allo-HSCT in children with AML. The study was approved by the Independent Ethics Committee and the Scientific Council of the I.P. Pavlov First Saint Petersburg State Medical University of Ministry of Healthcare of the Russian Federation. To assess MRD using standard diagnostic methods, we analyzed the data of 95 children with AML in their 1st–2nd remission (cohort 1). MRD status was negative in 67 (70.6 %) patients; in 28 (29.4 %) children, MRD status was positive according to molecular genetic studies and / or immunophenotyping results. For pre-transplant evaluation of the expression of genes characteristic of LSC, we investigated bone marrow samples of 50 patients (cohort 2) using real-time polymerase chain reaction. The DNMT3B, GPR56, CD34, SOCS2, SPINK2, FAM30A, and ABL genes were studied by real-time polymerase chain reaction, followed by calculation of the pLSC6 value using the formula: DNMT3b × 0.189 + GPR56 × 0.054 + CD34 × 0.0171 + SOCS2 × 0.141 + SPINK2 × 0.109 + FAM30A × 0.0516. At the time of allo-HSCT, 37 (74 %) children with AML were in their 1st or 2nd remission of the disease, 13 (26 %) were out of the 1st–2nd remission. With a median follow-up of 5 years in the group of patients with a positive MRD status, determined by standard methods (cohort 1), overall survival (OS) was 67.9 % vs 73.1 % for patients with a negative MRD status (p = 0.83). The cumulative incidence of relapse was 50 % and 22 %, respectively; p = 0.012. When assessing the level of expression of genes characteristic of LSC (cohort 2), a pLSC6 level was above the median in 18/37 (49 %) patients. The results of linear regression showed that the pre-transplant level of expression of genes characteristic of LSC was not associated with the number of blasts/MRD (odds ratio 1.002; 95 % confidence interval 0.979–1.025). One-year OS rates did not differ significantly in children in the 1st–2nd remission of AML, depending on pLSC6 level: 84.2% in patients with low pLSC6 and 72.2 % – with high pLSC6 (p = 0.4), event-free survival in the corresponding groups – 68.4 % and 61.1 %, respectively (p = 0.34). The cumulative incidence of early relapse after allo-HSCT in the group of AML patients with a high pLSC6 score was significantly higher than in children with a low pLSC6 score before allo-HSCT (22 % and 0 %, respectively; p = 0.03). MRD does not have a statistically significant effect on OS. However, MRD positivity before allo-HSCT increases cumulative incidence of relapse. The level of expression of genes characteristic of LSC, determined before allo-HSCT, showed a prognostic significance in relation to the development of early AML relapse after allo-HSCT.

Extramedullary involvement in pediatric myeloid leukemia: challenges of diagnosis and treatment. Clinical cases and a literature review

The problem of extramedullary (EM) involvement in acute myeloid leukemia (AML) in children is of considerable relevance since its pathogenesis remains understudied and the impact on prognosis is still unclear. The variability of tissue and organ involvement depends on immunophenotypic, cytogenetic, and molecular features of myeloid cells and can cause difficulties in diagnosis, thus making it necessary to combine imaging and laboratory tools for timely and accurate diagnosis of EM disease. The prognostic significance of EM involvement has not been established unequivocally, thus the need for intensification of chemotherapy, as well as for allogeneic hematopoietic stem cell transplantation in first remission, remain debatable. The results of target therapy in EM AML are encouraging and may reduce the risk of AML relapse. This article describes the clinical features of EM AML in children and reviews the diagnostic approaches as well as the advantages and limitations of existing laboratory and imaging methods. The molecular features of EM AML, current treatment options and prognosis have also been analyzed. The patients' parents gave their consent to the use of their children's data, including photographs, for research purposes and in publications.

A Phase 1/2 Dose Escalation Study of the Myeloid Kinase Inhibitor HM43239 in Patients with Relapsed or Refractory Acute Myeloid Leukemia

INTRODUCTION: HM43239 is an oral kinase inhibitor that potently inhibits myeloid kinases including diverse forms of the FLT3, SYK, JAK1/2, and mutant KIT kinases. These kinases and their mutant forms drive aberrant activation of downstream proliferation pathways and are associated with a high risk of relapse in AML. In a preclinical xenograft and orthotopic model of AML, HM43239 exhibited greater antitumor potency than FLT3 inhibitor gilteritinib, SYK inhibitor entospletinib, BCL-2 inhibitor venetoclax, and demethylation agent azacitidine. HM43239 is being evaluated in an international Phase 1/2 trial in patients with relapsed or refractory (R/R) acute myeloid leukemia (AML). AIMS: The primary objectives are to assess the safety and tolerability of HM43239 and determine the recommended phase 2 dose in R/R AML patients. A key secondary objective is to elucidate the pharmacokinetic (PK) profile in dose escalation and expansion cohorts. METHODS: The study is enrolling R/R AML eligible patients into dose escalation and dose exploration cohorts. HM43239 is administered continuously as oral tablets once daily in 28-day cycles. Treatment emergent adverse events (TEAEs) and tumor responses are evaluated using CTCAE and Revised Recommendation International Working Group criteria, respectively. RESULTS: As of July 14, 2022, a total of 50 patients, 26 male and 23 female, median age 59.5 (range 18-84) years, 28 FLT3-WT (56%) and 22 FLT3 mutated (44%) (15 FLT3-ITD (30%), 4 FLT3-TKD (8%) and 3 (6%) FLT3-ITD and / TKD), with a median of 2 prior treatments (range 1-6), have been treated with HM43239 at dose levels of 20 mg (n=2), 40 mg (n=1), 80 mg (n=20), 120 mg (n=13), 160 mg (n=10), and 200 mg (n=4). Nine patients (18%) were previously treated with 1 to 2 FLT3 inhibitors. Six patients (12%) had drug related TEAEs of Grade ≥ 3 which include decreased neutrophil count and muscular weakness (n=2; 4% each), and decreased white blood cell count, leukopenia, and nausea (n=1; 2% each). One patient experienced a DLT (grade 3 muscle weakness upper and lower limb) at the 200 mg dose level, without evidence of rhabdomyolysis. No DLTs were reported up through 160 mg. No drug-related adverse events (AEs) of QT prolongation or CK elevation were noted, and no drug-related serious AEs or deaths were reported. Eight of 50 patients achieved clinical response at multiple dose levels including 80 mg, 120 mg, and 160 mg. These include 7 patients with a reported best response of composite complete remission (CRc, including complete remission [CR], complete remission with incomplete platelet recovery [CRp] and complete remission with incomplete hematological recovery [CRi]) and 1 with partial remission (PR). All responses were achieved 1 or 2 cycles after HM43239 was initiated. Among 7 CRc patients, 5 proceeded to hematopoietic stem cell transplantation (HSCT). Of 22 FLT3 mutated patients, 5 (18%) achieved clinical response (4 CRc and 1 PR). Importantly, 3 of 7 (43%) FLT3-mutated patients who received prior FLT3 inhibitor treatment including gilteritinib and/or midostaurin achieved a response (2 CRc and 1 PR). Of 28 WT-FLT3 patients, 3 (11%) achieved a CRc. Notably, patients with clinical responses had a variety of additional adverse resistance mutations of NPM1, MLL-PTD, IDH2, NRAS, KRAS, DNMT3A, RUNX1, PTPN11, TP53 and others, with or without FLT3 mutation. Markedly, a WT-FLT3 patient with a TP53 mutation achieved CR and continued treatment for 14 cycles. The steady-state PK exposure of HM43239 rose from 20 mg to 120 mg, but no further increase was observed at 160 mg. Considering this and the safety profile, 120 mg was chosen as the expansion single agent starting dose with potential adjustments from 80 to 160 mg upon further evaluation of safety, tolerability, and efficacy. CONCLUSIONS: As of July 14, 2022, HM43239 has delivered CRc at 80 mg, 120mg and 160 mg, and was well tolerated at these dose levels over multiple cycles with no DLTs or drug-related SAEs. Pharmacokinetic data illustrate increasing drug exposures through 120 mg and observed objective responses through 160 mg in both FLT3-WT and FLT3-mutated R/R AML patients even after gilteritinib and midostaurin treatment. An update of this study, including a planned single agent and venetoclax combination expansion, will be presented at the meeting. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P442: SPINK2 PROTEIN EXPRESSION QUANTIFIED BY IMMUNOHISTOCHEMISTRY REFINES RISK STRATIFICATION AND PREDICTS THERAPY OUTCOMES IN AML

Background: Suboptimal prognostication, therapy refractoriness and relapse contribute to the poor outcome of Acute Myeloid Leukemia (AML) patients. Leukemic stem cells (LSC) are considered crucial drivers of relapse and therapy resistance. Clinicopathological characterization of LSC-associated genes with convenient assessment tools such as immunohistochemistry (IHC) is needed. Our initial screening of AML datasets for LSC-associated genes identified Serine Protease Inhibitor Kazal type 2 (SPINK2) with high expression in AML, particularly in LSC fractions. However, in-depth analysis of its clinicopathological associations and prognostic utility in AML are lacking. Aims: To assess SPINK2 expression in adult AML with IHC, and determine its clinicopathological associations, prognostic impact and association with therapy response Methods: We studied the expression of SPINK2 by IHC in 172 non-M3 adult AML patients (median age:52yrs, range: 18-86yrs) treated at the Prince of Wales Hospital. The majority (90.8%) were de novo type and 72.3% had intermediate-risk(IR) cytogenetics, with 88.5% receiving Daunorubicin + Ara-C (DA 7 + 3) induction. SPINK2 expression was assessed by 3 hematopathologists in a double-blinded manner and quantified by a composite score (range: 0-16). Clinical data was collected for all cases. Results:SPINK2 staining in leukemic blasts was consistently cytoplasmic, and its protein expression strongly correlated with mRNA levels by qPCR in a subset of 128 patients (r=0.716, P<0.0001). The cohort was dichotomized at the median score 3, since this cut-off showed strongest association with poor event-free survival (EFS) and overall survival (OS). High SPINK2 (SPINK2hi) patients accounted for 77/172 (44.8%) cases, and low SPINK2 (SPINK2lo) patients for 95/172(55.2%). SPINK2hi associated with IR cytogenetics (P=0.014), normal karyotype (P=0.019) and NPM1 mutation (P<0.001), while SPINK2lo with t(8;21) and CEBPA double-mutation (both P<0.001). Survival and treatment-response analyses were performed on a subgroup of 137 patients who received DA 7 + 3 based induction. SPINK2hi patients had lower CR rates (73.8% vs 88.3%,P=0.028), higher 6-month relapse rates (31.8% vs 9.1%,P=0.004), lower 5-yr RFS (25.8% vs 46.8%,P=0.004), EFS (16.6% vs 37.2%,P<0.001) and OS (25.3% vs 51.2%,P<0.001). SPINK2 status also identified high risk patients of the IR cytogenetic subgroup. Of these, SPINK2hi patients had lower CR rates (68.6% vs 90.0%,P=0.013), higher 6-month relapse rates (31.4% vs 6.9%,P=0.018), lower 5-yr RFS(27.0% vs 44.6%,P=0.018), EFS(15.4% vs 38.3%,P<0.001) and OS(22.9% vs 51.5%,P=0.002). In this subgroup, median SPINK2 score was higher in patients requiring ≥2 inductions to achieve CR vs. patients requiring 1 course (7 vs 2,P=0.009). Multivariate analyses in whole and IR cytogenetics cohorts showed the poor prognostic effect of SPINK2hi on EFS and OS independent of age, cytogenetic risk, mutations and achievement of CR1, including stem cell transplantation given in CR (Table 1). In our NPM1mut subgroup (N=41), SPINK2hi status associated with poor EFS (HR:3.3,P=0.04) and OS (HR: 4.0,P=0.007) independent of age and FLT3-ITD with high allelic ratio. Incorporation of SPINK2 with FLT3 status refined ELN2017 risk definition, whereby 15/22 favorable-risk patients could be reclassified as intermediate-risk. Image:Summary/Conclusion: High SPINK2 protein expression by IHC predicted increased chemoresistance and early relapse risk in AML, and was an independent adverse prognostic biomarker, particularly in patients with intermediate-risk cytogenetics and NPM1 mutations.

Rational biomarker development for the early and minimally invasive monitoring of AML

AbstractRecurrent disease remains the principal cause for treatment failure in acute myeloid leukemia (AML) across age groups. Reliable biomarkers of AML relapse risk and disease burden have been problematic, as symptoms appear late and current monitoring relies on invasive and cost-ineffective serial bone marrow (BM) surveillance. In this report, we discover a set of unique microRNA (miRNA) that circulates in AML-derived vesicles in the peripheral blood ahead of the general dissemination of leukemic blasts and symptomatic BM failure. Next-generation sequencing of extracellular vesicle-contained small RNA in 12 AML patients and 12 controls allowed us to identify a panel of differentially incorporated miRNA. Proof-of-concept studies using a murine model and patient-derived xenografts demonstrate the feasibility of developing miR-1246, as a potential minimally invasive AML biomarker.

Persistent Somatic Mutation at Remission Is Associated with Poor Survival and Higher Risk of Relapse in Patients with Acute Myeloid Leukemia

IntroductionMinimal residual disease (MRD) measured by multi-color flow cytometry has been associated with an increased risk of relapse in patients with acute myeloid leukemia (AML). There is also a strong interest in using somatic mutation as an MRD marker and persistence of NPM1 mutation after 2 cycles of induction therapy has been shown to increase the risk of relapse in AML (Ivey et al, NEJM 2016). However, only one third of AML patients carry NPM1 mutation and prognostic impact of persistent mutations in the context of other co-occurring mutations and association with flow cytometry measured MRD is not well understood.MethodsWe studied 95 patients with previously untreated AML who received frontline induction chemotherapy and subsequently achieved complete remission (CR). Paired bone marrow samples obtained at pre-treatment and CR (median day 31) were analyzed by targeted capture exome sequencing of 295 genes (median 309x coverage). Mutect and Pindel was used to call single nucleotide variants (SNVs) and small indels, respectively. We defined two levels of mutation clearance (MC) based on the variant allele frequency (VAF) of the detected mutations at CR: 1) MC2.5, if persistent mutation with VAF <2.5%, and 2) MC1.0 if persistent mutation with VAF <1%. Overall survival (OS), relapse free survival (RFS), event free survival (EFS), and cumulative incidence of relapse (CIR) considering non-relapse death as a competing event were calculated from the date of CR.ResultsOf 95 patients, 49 (52%) were male and 46 (48%) were female. The median age was 53 (range: 17-76). Conventional karyotyping showed one (1%) patient with favorable cytogenetics (CG), 70 (74%) with intermediate CG, and 21 (22%) with adverse CG (all defined by ELN criteria). Eighty nine (94%) patients had de novo AML and 6 (6%) had secondary AML. Thirty-nine (41%) patients underwent allogeneic stem cell transplant in first CR. In the pre-treatment samples of 95 AML patients, we detected 299 high-confidence somatic mutations (192 SNVs and 107 indels) in 60 genes in 85 (89%) patients. The most frequently mutated genes were NPM1 (31%) followed by DNMT3A (29%), FLT3 (18%), and IDH2 (18%). In the matching CR samples, 84 (28%) and 108 (36%) mutations persisted at the level of VAF ≥2.5% and ≥1%, respectively, which corresponded to 41 (48%) and 31 (36%) patients achieving MC2.5 and MC1.0, respectively. Pattern of MC was distinct between mutated genes and affected molecular pathways (Table1). Mutations associated with clonal hematopoiesis of indeterminate potential (CHIP), DNA methylation, and splicing had low rate of MC, whereas mutations in transcription factor genes or receptor tyrosine kinase (RTK) pathway had high rate of MC. With the median follow-up of 41 months (95% CI: 39-47), patients who achieved MC1.0 had significantly better RFS, EFS, OS and lower CIR than those without MC1.0, while there was no significant difference in any of the above outcomes by MC2.5 (Table 2). Flow cytometry-based MRD (flow-MRD) data were available in 92 (97%) patients at CR. Positive flow-MRD was associated with significantly worse RFS, EFS, OS and CIR (Table2). Among 61 patients with negative flow-MRD, 25 (41%) and 32 (52%) had persistent mutations with VAF ≥2.5% and ≥1%, respectively. Multivariable analysis considering mutations that were prognostic in univariable analysis (NPM1, IDH1), age, ELN-defined adverse cytogenetics, flow-MRD and MC revealed that MC1.0 was a significant prognostic factor for RFS (p = 0.03, HR 0.36, 95%CI: 0.14-0.91) and CIR (p = 0.03, HR 0.42, 95%CI: 0.19-0.92). MC1.0 in DNA methylation (2-year EFS: 85% (95% CI: 51-96) in MC1.0 vs. 40% (95% CI: 23-56) in non-MC1.0, p = 0.01; 2-year OS: 85% (95% CI: 51-96) in MC1.0 vs. 58% (95% CI: 39-72) in non-MC1.0, p = 0.03) or in chromatin-cohesin pathways (2-year EFS: 73% (95% CI: 37-90) in MC1.0 vs. 15% (95% CI: 3-39) in non-MC1.0, p < 0.01; 2-year OS: 82% (95% CI: 45-95) in MC1.0 vs. 39% (95% CI: 14-63) in non-MC1.0, p < 0.01) was associated with significantly better EFS and OS.ConclusionIn patients with AML treated with induction chemotherapy, persistent somatic mutation at CR with VAF >1% was associated with increased risk of death and relapse. Assessment of both mutation clearance and flow-based MRD at CR may help further risk stratification of AML. [Display omitted] DisclosuresDaver:Immunogen: Research Funding; Kiromic: Research Funding; Bristol-Myers Squibb Company: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding; Incyte Corporation: Honoraria, Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Otsuka America Pharmaceutical, Inc.: Consultancy; Sunesis Pharmaceuticals, Inc.: Consultancy, Research Funding; Daiichi-Sankyo: Research Funding; Jazz: Consultancy; Pfizer Inc.: Consultancy, Research Funding. Cortes:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Sun Pharma: Research Funding; BMS: Consultancy, Research Funding. Jabbour:Bristol-Myers Squibb: Consultancy. Kantarjian:Bristol-Meyers Squibb: Research Funding; ARIAD: Research Funding; Delta-Fly Pharma: Research Funding; Pfizer: Research Funding; Amgen: Research Funding; Novartis: Research Funding. Takahashi:Symbio Pharmaceuticals: Consultancy.

Prognostic Role of Multiparameter Flow Cytometry-Based Measurable Residual Disease Assessment in Patients with Acute Myeloid Leukemia Harboring DNMT3A/TET2/ASXL1 Mutation

Prognostic Role of Multiparameter Flow Cytometry-Based Measurable Residual Disease Assessment in Patients with Acute Myeloid Leukemia Harboring DNMT3A/TET2/ASXL1 Mutation

Hematologic Predictors of Outcomes in Patients Undergoing Intensive Induction Chemotherapy for Newly Diagnosed Acute Myeloid Leukemia

Background Presently, acute myeloid leukemia (AML) risk stratification is estimated prior to treatment by incorporating patient and disease characteristics. However, apart from the limited use of minimal residual disease measurement, few methodologies assess AML relapse risk post-treatment. In attempts to correlate pre- and post-treatment blood cell counts with hematologic disease outcomes, the ratio, LNR, between absolute lymphocyte count (ALC) and neutrophils (ANC) has been utilized to approximate the relationship between the lymphoid system and the myeloid microenvironment (in particular myeloid-derived suppressor cells), and increased LNR is prognostic in myeloma and lymphoma. Similarly, increased LMR (lymphocyte to monocyte ratio), utilized as a crude marker of tumor-infiltrating lymphocytes and tumor-associated macrophages, predicts better outcomes in Hodgkin's disease (Romano et al. Ann Hematol2018). However, analyses correlating such ratios with AML outcomes have not been performed. Here we specifically investigate whether LNR, LMR, or neutrophil-monocyte (NMR) ratios, measured at multiple time-points, correlate with outcomes. Methods We identified patients &amp;gt;18 yrs receiving induction chemotherapy at our institution between 1/1/2005 - 12/31/2019. Data collected included demographics, comorbidities (Charlson Comorbidity Index [CCI]), AML subtype, cytogenetics/molecular data, ELN risk stratification, and response to therapy. We recorded patients' total WBC, ANC, ALC and AMC both prior to treatment, at first ANC recovery (ANC &amp;gt; 1.0 x 109/L with ALC and AMC &amp;gt; 0), and just prior to next therapy. We also identified a subset of patients who received consolidation chemotherapies with curative intent and collected their first WBC counts ~100 days post-therapy completion (range 50-150 days). The calculated LNR, LMR, and NMR at these time-points were correlated with Event-Free Survival (EFS), defined as time to relapse, death from any cause, or last follow-up. Data was censored on 6/1/2020. WBC ratios were categorized into tertiles. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models, survivor functions estimated using Kaplan-Meier and the equality of survivor functions tested using stratified log-rank tests. Outcomes were adjusted for CCI, age, sex, race, subtype, presence of inflammation/infection, and ELN risk. Results 145 patients met eligibility criteria, however 23 with primary refractory AML were excluded from EFS analysis. Using WBC ratios at first ANC recovery, both intermediate and high LNR trended towards a lower HR for EFS: HR 0.54 (95% CI 0.24-1.23,p= 0.142) and 0.68 (95% CI 0.32-1.33,p= 0.329), respectively, however differences were not statistically significant (Table 1 and Figure 1). A high NMR also trended towards a worse EFS: HR 1.71 (95% CI 0.74-3.99,p= 0.212), though it was also not statistically significant. LMR did not correlate with improved EFS. Notably, pre-induction ratios and the ratios measured just prior to next treatment were not associated with any differences in EFS. In a subset of patients who received curative intent consolidation chemotherapies (generally ELN favorable risk), a t-test correlating for relapse was performed, though limited by small numbers (16 without, 8 with relapse). Patients in this group who did not relapse trended toward a numerically higher LNR and LMR, 0.57 vs 0.50 (p =0.36) and 4.33 vs 3.97 (p= 0.39), respectively. Discussion In our patient population, high LNR after induction chemotherapy trended towards predicting an improved EFS. Thus, recovery WBC ratios, although crude approximations of the immune system and the tumor microenvironment, may predict patients at higher risk of relapse, however, more patients are clearly needed to show whether a statistically significant association exists. The optimal time to evaluate these counts is also not clear. Nonetheless, as blood counts are obtained routinely post-treatment, these ratios may represent a low-cost strategy to predict relapse risk, potentially allowing for earlier treatment and donor searches for allogeneic transplantation. We propose to repeat these analyses using a multi-center approach - we are especially interested in ratios measured at the 100 days post-therapy mark, as we suspect these may better reflect the immune system at steady state and, potentially, risk of relapse. Disclosures Arain: Astellas:Other: Spouse is employed.Calip:Flatiron Health:Current Employment.Khan:Takeda:Research Funding;Celgene:Consultancy;Incyte:Honoraria;Amgen:Consultancy.Patel:Amgen:Consultancy;Janssen:Consultancy;Celgene:Consultancy.Quigley:Amgen:Other: Advisory board;Agios:Speakers Bureau;Alnylam:Speakers Bureau.

Choreography of methylation: KDM4C histone demethylation enables ALKBH5 m6A RNA demethylation to sustain AML stem cells.

Choreography of methylation: KDM4C histone demethylation enables ALKBH5 m6A RNA demethylation to sustain AML stem cells.

Reduced Relapse Risk in Children with Acute Myeloid Leukemia (AML) Who Experience Septic Shock (SS)

Background: Relapse remains the major clinical risk in children with AML, and persistent minimal residual disease (MRD) poses a particular therapeutic challenge as a presumably chemoresistant cell population. We previously showed innate immune stimulation can generate durable memory immune responses against leukemia cells in preclinical MRD models (Blood 2009 114:2459; Leukemia 2018 32: 539). These treatments mimic the "danger" signal provided by SS and may offer novel immunotherapeutic approaches for patients who fail or are not eligible for targeted immunotherapies. Demonstrating a protective effect of SS against AML relapse would support clinical development of innate immune stimulants. We hypothesized 1) SS is associated with a decreased risk of AML relapse among children who were able to achieve remission after induction, and 2) this effect is most pronounced in children with persistent MRD, who are more likely to have both SS exposures and relapses. Methods: We used a previously assembled cohort of children with de novo AML using Pediatric Health Information System (PHIS) data merged with patients on two clinical trials from the Children's Oncology Group (COG; PLOS One 2015 10:e0143480). We developed and validated a method to detect SS exposures in PHIS using vasopressor billing codes (PBC 2019 10.1002/pbc.27713 #2024) and used COG data for demographics, treatment, and outcomes. SS exposures were captured starting 7 days from first chemotherapy until last day of the last treatment course or 30 days prior to relapse. Follow-up for relapse and non-relapse mortality (NRM) began after the end of Induction II and continued to last contact, off-study date, or until 5 years from diagnosis. Cumulative incidences of relapse (CIR) and NRM (CIN) were estimated treating each other as competing risks. Sub-distribution hazard regression models were used to estimate crude and adjusted sub-hazard ratios (subHR) and associated 95% confidence intervals (CI) of relapse in relation to SS. SS was treated as a time-varying exposure, so each patient became SS-exposed once the first SS occurred. Demographic and clinical characteristics were evaluated as potential confounders of the associations of interest. Results: We identified 569 COG-PHIS patients with AML who achieved complete remission by the end of Induction II. In this cohort, 188 (33%) experienced SS during therapy. Older age, Black non-Hispanic race-ethnicity, Hispanic ethnicity, and receipt of stem cell transplant (SCT) were associated with SS exposure (Table 1). Median follow-up was 1122 days (IQR 413-1745) from the end of Induction II. Relapse occurred in 220 (38.7%) patients and was associated with male sex and genetic risk (Table 1). Positive end-Induction I MRD approached a significant association with relapse. CIRs were similar among SS-exposed and unexposed patients in the overall cohort and in MRD-negative patients (Figs. 1A-B). Among children with persistent MRD, SS-exposed patients had a lower 5-year CIR than unexposed patients (43% vs. 60.1%; Fig. 1C). Adjusted subHR for relapse for the overall cohort was 0.82 (CI: 0.61-1.11); for the MRD-negative subgroup, adjusted subHR was 0.86 (CI: 0.61-1.21); and for the MRD-positive subgroup, 0.57 (CI: 0.31-1.05). These effects were consistently in the protective direction but did not reach statistical significance. In a sensitivity analysis restricting duration of the exposure effect to 12 months, SS exposure in the overall cohort was associated with a risk reduction (adjusted subHR 0.65; CI: 0.45-0.92). NRM occurred in 28 (4.9%) and was associated with high-risk therapy on AAML1031 and with positive MRD, with a near-significant association with SCT (not shown). SS-exposed patients had a higher 5-year CIN (10.4% v. 2.8%; Fig. 1D). Conclusions: Using merged clinical trial and administrative data, we identified a potentially protective effect of exposure to a strong immune stimulus (SS) that was most pronounced in children with persistent MRD. This suggests immune surveillance for low-level AML can be induced and supports investigation of innate immune stimulant therapy for this very poor prognosis childhood leukemia. While NRM is higher among SS-exposed patients, clinical trials of innate immune stimulants would comprise controlled interventions expected to result in markedly less toxicity than unpredictable SS exposures. Repeated dosing may prolong the effect duration beyond 12 months. Disclosures Fisher: Merck: Research Funding; Pfizer: Research Funding; Astellas: Other: Data Safety Monitoring Board Chair for an antifungal study.

T cell receptor gene therapy targeting WT1 prevents acute myeloid leukemia relapse post-transplant.

Relapse after allogeneic hematopoietic cell transplantation (HCT) is the leading cause of death in patients with acute myeloid leukemia (AML) entering HCT with poor-risk features1-3. When HCT does produce prolonged relapse-free survival, it commonly reflects graft-versus-leukemia effects mediated by donor T cells reactive with antigens on leukemic cells4. As graft T cells have not been selected for leukemia specificity and frequently recognize proteins expressed by many normal host tissues, graft-versus-leukemia effects are often accompanied by morbidity and mortality from graft-versus-host disease5. Thus, AML relapse risk might be more effectively reduced with T cells expressing receptors (TCRs) that target selected AML antigens6. We therefore isolated a high-affinity Wilms' Tumor Antigen 1-specific TCR (TCRC4) from HLA-A2+ normal donor repertoires, inserted TCRC4 into Epstein-Bar virus-specific donor CD8+ T cells (TTCR-C4) to minimize graft-versus-host disease risk and enhance transferred T cell survival7,8, and infused these cells prophylactically post-HCT into 12 patients ( NCT01640301 ). Relapse-free survival was 100% at a median of 44 months following infusion, while a concurrent comparative group of 88 patients with similar risk AML had 54% relapse-free survival (P = 0.002). TTCR-C4 maintained TCRC4 expression, persisted long-term and were polyfunctional. This strategy appears promising for preventing AML recurrence in individuals at increased risk of post-HCT relapse.

Early Cytomegalovirus Reactivation and Donor Constellation Reduce Early and Late Relapse Incidence of Acute Myeloid Leukemia in a Long-Term Study

IntroductionAfter allogeneic cell transplantation (HCT) for acute myeloid leukemia (AML) relapse remains the main cause of morbidity and mortality. Relapse rates directly translate into patients' overall survival. The connection between early human cytomegalovirus (CMV) replication and reduced leukemic recurrence has first been established by this group (Elmaagacli et. al. Blood 2011), using a pp65-antigenemia assay and confirmed by Green et al. (Blood 2013), Takenaka et al. (BBMT 2015) and others. In a more recent study by Teira et al. (Blood 2016) using PCR to detect reactivation, this effect has been questioned and the controversy remains probably due to methodological differences between studies.MethodsPatients with AML received allogeneic HCT at the Department of Bone Marrow Transplantation of the University Hospital Essen between 10/1997 and 10/2017. All patient-, donor-, HCT- and virology data was prospectively documented and retrospectively analyzed. The immunosuppressive regimen consisted of cyclosporine A and methotrexate. The conditioning was according to physician's choice and included only non-anti-thymocyte globuline (ATG) conditioning regimens. Early supportive and follow-up care was identical for all patients. Patients were followed for up to 60 months. Surviving patients were censored at last follow-up date. Competing risk analysis was performed for calculating cause-specific relapse-incidences with non-relapse mortality as competing risk. CMV titers were measured at the Department of Virology using quantitative PCR (qPCR) and a pp65 antigenemia assay. CMV reactivation was defined as a replication of >500 CMV copies per ml EDTA blood or as >25 pp65 antigen expressing cells per 5×105 white blood cells. If several CMV reactivation episodes occurred, only the interval to the first episode after HCT was analyzed.ResultsA total of 420 consecutive adult patients (median age, 48 years; range, 16-73 years) with AML and HCT were included for analysis. Over 60 months of follow-up, cumulative incidence of CMV reactivation was detected in 28% of patients and AML relapsed in 34%. In this cohort, the sensitivity of qPCR or pp65 detection methods did not differ (p=0.35) with regard to the incidence of CMV reactivation. CMV reactivation associated with significantly reduced AML relapse risk. The relapse incidence (RI) for patients with CMV reactivation was 0.18 (95% Confidence interval (CI), 0.12-0.25) compared to 0.41 (95% CI, 0.35-0.46) for patients without CMV reactivation (p<0.0001). This significant difference was reproduced for prognostic AML subgroups in first complete remission (RI, 0.14 with CMV reactivation versus 0.35 without; p=0.02) and for higher risk AML (RI, 0.20 versus 0.45; p<0.0001). Notably, donor-recipient serostatus constellation significantly (p=0.005) associated with AML relapse reduction, independently of CMV reactivation. CMV positive donors had a RI of 0.40 (95% CI, 0.33-0.46) compared to 0.28 in CMV negative donors (95% CI, 0.22-0.34).DiscussionThis new PCR dataset confirms previous reports (Elmaagacli et al. 2011; Takenaka et al. 2015) of an independent reduction of AML relapse risk after CMV reactivation, using qPCR detection in a homogeneous population of AML patients. While the association between CMV reactivation and early relapse (< day+100) has also been confirmed by Green et al. (Blood 2013) and relapse (>day +100) by Takenaka et al. (BBMT 2015), our data shows that late relapse (>24 months) may occur in patients without CMV reactivation. While the aforementioned studies exclusively used pp65 antigenemia titers as a determinant of CMV reactivation, Teira et al. (Blood 2016) analyzed PCR samples. The sensitivity of CMV reactivation using PCR or pp65 antigen titers was identical in our dataset. With regard to the on-going controversy on the role of CMV reactivation and AML relapse, this data shows a reduction of relapse in the quantitative PCR age. [Display omitted] DisclosuresTurki:Neovii Biotech: Other: subsidies for the costs of travel. Beelen:Medac: Consultancy, Other: Travel Support.

Association between OGG1 S326C CC genotype and elevated relapse risk in acute myeloid leukemia.

Recent studies have shown that tumors of relapsed acute myeloid leukemia (AML) present additional genetic mutations compared to the primary tumors. The base excision repair (BER) pathway corrects oxidatively damaged mutagenic bases and plays an important role in maintaining genetic stability. The purpose of the present study was to investigate the relationship between BER functional polymorphisms and AML relapse. We focused on five major polymorphisms: OGG1 S326C, MUTYH Q324H, APE1 D148E, XRCC1 R194W, and XRCC1 R399Q. Ninety-four adults with AML who achieved first complete remission were recruited. Genotyping was performed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The OGG1 S326C CC genotype (associated with lower OGG1 activity) was observed more frequently in patients with AML relapse [28.9 vs. 8.9%, odds ratio (OR) = 4.10, 95% confidence interval (CI) = 1.35-12.70, P = 0.01]. Patients with the CC genotype exhibited shorter relapse-free survival (RFS). Moreover, the TCGA database suggested that low OGG1 expression in AML cells is associated with a higher frequency of mutations. The present findings suggest that the OGG1 S326C polymorphism increased the probability of AML relapse and may be useful as a prognostic factor for AML relapse risk.

Base Excision Repair Gene OGG1 Affects the Relapse Risk of Acute Myeloid Leukemia

Background: Approximately 80% of acute myeloid leukemia (AML) patients can achieve complete remission, but around half of them relapse within five years. Recent studies have shown that AML relapse is associated with additional genetic mutation calls gclonal evolutionh in leukemic cell population (Ding, et al. Nature. 2012 & Parkin B, et al. Blood. 2013). These studies suggested that cytotoxic chemotherapy damaged cellular DNA and caused genetic mutation. In fact, anthracycline can produce 8-oxoguanine (8-OG) through induction of oxidative stress. 8-OG is most common DNA damage, which cause G:C to T:A transversion mutation. It is reported that transversion mutation more frequently observed in relapsed AML than primary AML. Base excision repair (BER) plays important role to correct base lesion including 8-OG and suppress genetic mutation. Therefore, we hypothesized BER gene polymorphisms may affect the risk of AML relapse, and focused five major functional polymorphisms: OGG1 S326C, MUTYH Q324H, APE1 D148E, XRCC1 R194W and XRCC1 R399Q.Material & Method: Ninety-four consecutive adults with AML who had achieved their first complete remission were recruited (male: 52, female: 42, age: 15-83 years, median age: 55.7 years). To remove the bias of the group, we also evaluated the risk in patients of non-M3 and under 65 years old (male: 22, female: 19, age: 15-64 years, median age: 49.0 years) (trimming group). These patients treated on Japan Adult Leukemia Study Group (JALSG) treatment protocols consisted of daunorubicin or idarubicin plus cytarabine (JALSG AML95, AML97, AML201, AML209). Genotyping was performed by PCR-RFLP method. The X2-test was used to compare the distribution of genotype and allele frequencies in patients. Leukemia-free survival (LFS) was calculated using the Kaplan-Meier method. Survival curves were compared using the log-rank test. In multivariate analysis, a stepwise selection procedure was performed using the proportional hazards Cox model for LFS. The variables were chosen with reference to previous studies; age, sex, white blood cell count and lactate dehydrogenase at diagnosis, number of induction courses, stem cell transplantation, MRC classification and history of tumor. This study was approved by the Institutional Review Board of Gunma University Hospital.Results: The OGG1 S326C CC genotype was observed significantly more often in the relapsed group (28.9% vs. 8.9%, OR = 4.10, 95% CI = 1.35-12.70, p = 0.01). In trimming group, the CC genotype was also observed more frequently in the relapsed group (50.0% vs. 6.9%, OR = 13.5, 95% CI = 2.17-84.0, p = 0.002). In addition, the OGG1 S326C CC genotype experienced a shorter median LFS than those with a non-CC genotype (CC vs. non-CC = 27.0 months vs. not reached, p = 0.02) (Figure 1). This genotype was also associated with poor LFS in trimming group (CC vs. non-CC = 11.0 months vs. not reached, p < 0.001) (Figure 1). Furthermore, multivariate analysis of LFS revealed OGG1 S326C CC genotype as an independent prognostic factor (HR = 4.32, 95% CI = 1.70-11.0, p = 0.002), like age, number of induction courses, and MRC classification (Table 1). Other polymorphisms had no significant effect on the risk of relapse.Conclusion: We previously reported that mutations by 8-OG were more efficiently suppressed in OGG1-S326 transduced cells than in OGG1-C326 transduced cells. Therefore, we hypothesized that low OGG1 activity promotes relapse of AML. To the best of our knowledge, this is the first report to show an association between BER gene polymorphisms and the relapse of AML. Our data suggest that OGG1 S326C can be a prognostic factor for AML relapse. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Revisiting Graft-Versus-Leukemia Effects after Umbilical Cord Blood Transplantation for Acute Myeloid Leukemia : A Report from Eurocord, the Acute Leukemia Working Party and the Cord Blood Committee of the Cellular Therapy & Immunobiology Working Party of the European Society for Blood and Marrow Transplantation

Background. The efficacy of umbilical cord blood transplantation (UCBT) as treatment for acute myeloid leukemia (AML) relies heavily on immune-mediated graft-versus-leukemia effects. Following bone marrow or peripheral blood stem cell transplantation, there is a strong association between occurrence of graft-versus-host disease (GVHD) and a lower risk of AML relapse. Here, we evaluated the kinetics of relapse rate in correlationto GVHD occurrence after UCBT.Methods. The study population included adult patients with de novo or secondary AML, receiving single or double UCBT between 2004 and 2014 at EBMT-affiliated centers.The kinetics of relapse rate over time in correrlation to occurence of GVHD was assessed by calculating the relapse rate per patient-year within sequential 90-day intervals (as previously reported by Inamoto et al., Blood 2011, 14 : 456-463). The smoothed rates were plotted as curves for each GVHD condition (no GVHD, acute GVHD or chronic GVHD). The impact of GVHD on relapse and overall mortality was also assessed with Cox models adjusted for patient age, status at transplantation, cytogenetics, total nucleated cells (TNC), and single versus double UCBT, modeling acute and chronic GVHD as time-dependent covariates.Results. The study included data from 1069 patients given single (n=567) or double (n=501) UCBT. Median patient age at transplantation was 45 (range, 18-73) years. The proportion of patients with grade II, III and IV acute GVHD was 20%, 7% and 4%, respectively. At 2 years, the cumulative incidence of chronic GVHD was 42%, the cumulative incidence of relapse was 32% and overall survival was 32% as well. As shwon in the figure 1, relapse rates declined gradually over time during the first 30 months after transplantation and were lower in patients with chronic GVHD than in those without GVHD. Furthermore , in a multivariate Cox model, there was a suggestion for lower incidence of relapse in patients who experienced chronic GVHD (HR 0.6, P=0.1). In contrast, there was a significant increase in the risk of mortality in patients with grade III-IV acute (HR 2.4, P<0.001) and those with de novo chronic GVHD (HR 3.2, P<0.001) due to increased non relapse mortality.Conclusions. Although this study suggest that chronic GVHD might be associated with lower risk of AML recurrence after UCBT, grade III-IV acute and chronic GVHD each increased overall mortality. [Display omitted] DisclosuresMichallet:Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Astellas Pharma: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria.

MCM7 polymorphisms associated with the AML relapse and overall survival.

The minichromosome maintenance complex component 7 (MCM7) encodes a member of MCM complex, which plays a critical role in the initiation of gene replication. Due to the importance of MCM complex, MCM7 gene has been regarded as a candidate gene for cancer development. In the present study, seven MCM7 polymorphisms were genotyped in 344 subjects composed of 103 acute myeloid leukemia (AML) patients and 241 normal controls to examine the possible associations between MCM7 polymorphisms and the risk of AML. MCM7 polymorphisms were not associated with the risk of AML (P > 0.05). However, MCM7 polymorphisms were significantly related to the relapse of AML and overall survival. The rs2070215 (N144S) showed a protective effect to the risk of AML relapse (OR = 0.37; P corr = 0.02). In haplotype analyses, the ht1 and ht2 showed significant associations with the risk of AML relapse (P corr = 0.02-0.03). In addition, rs1534309 showed an association with the overall survival of AML patients. Patients with major homozygote genotype (CC) of rs1534309 showed a higher survival rate than the patients with other genotypes (CG and GG). The results of the present study indicate that MCM7 polymorphisms may be able to predict the prognosis of AML patients.

Multigene Measurable Residual Disease Assessment Improves Acute Myeloid Leukemia Relapse Risk Stratification in Autologous Hematopoietic Cell Transplantation

We report here the largest study to date of adult patients with acute myeloid leukemia (AML) tested for measurable residual disease (MRD) at the time of autologous hematopoietic cell transplantation (auto-HCT). Seventy-two adult patients who underwent transplantation between 2004 and 2013 at a single academic medical center (University of California San Francisco) were eligible for this retrospective study based on availability of cryopreserved granulocyte colony–stimulating factor (GCSF)–mobilized autologous peripheral blood progenitor cell (PBPC) leukapheresis specimens (“autografts”). Autograft MRD was assessed by molecular methods (real-time quantitative PCR [RQ-PCR] for Wilms tumor 1 (WT1) alone or a multigene panel) and by multiparameter flow cytometry (MPFC). WT1 RQ-PCR testing of the autograft had low sensitivity for relapse prediction (14%) and a negative predictive value of 51%. MPFC failed to identify MRD in any of 34 autografts tested. Combinations of molecular MRD assays, however, improved prediction of post–auto-HCT relapse. In multivariate analysis of clinical variables, including age, gender, race, cytogenetic risk category, and CD34+ cell dose, only autograft multigene MRD as assessed by RQ-PCR was statistically significantly associated with relapse. One year after transplantation, only 28% patients with detectable autograft MRD were relapse free, compared with 67% in the MRD-negative cohort. Multigene MRD, while an improvement on other methods tested, was however suboptimal for relapse prediction in unselected patients, with specificity of 83% and sensitivity of 46%. In patients with known chromosomal abnormalities or mutations, however, better predictive value was observed with no relapses observed in MRD-negative patients in the first year after auto-HCT compared with 83% incidence of relapse in the MRD-positive patients (hazard ratio, 12.45; P = .0016). In summary, increased personalization of MRD monitoring by use of a multigene panel improved the ability to risk stratify patients for post–auto-HCT relapse. WT1 RQ-PCR and flow cytometric assessment for AML MRD in autograft samples had limited value for predicting relapse after auto-HCT. We demonstrate that cryopreserved autograft material presents unique challenges for AML MRD testing because of the masking effects of previous GCSF exposure on gene expression and flow cytometry signatures. In the absence of information regarding diagnostic characteristics, sources other than GCSF-stimulated PBSC leukapheresis specimens should be considered as alternatives for MRD testing in AML patients undergoing auto-HCT.

Granulocyte Colony-Stimulating Factor–Mobilized Allografts Contain Activated Immune Cell Subsets Associated with Risk of Acute and Chronic Graft-versus-Host Disease

We defined associations among immune cell subsets in granulocyte colony-stimulating factor (G-CSF)–mobilized allografts and clinical outcomes after allogeneic hematopoietic cell transplantation (alloHCT). Fresh peripheral blood stem cell (PBSC) aliquots from 238 G-CSF–mobilized allografts were extensively characterized by immunophenotype. Subset-specific transplanted cells were correlated with acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), malignant disease relapse, nonrelapse mortality, and overall survival. Of 238 assessable alloHCT recipients, 185 patients (78%) received reduced-intensity conditioning and 152 (64%) antithymocyte globulin-based serotherapy. Incidences of aGVHD and cGVHD were 58% and 48%, respectively. Median follow-up was 21 months (range, 1.4 to 41.1). In multivariable analyses adjusted for relevant clinical factors, allograft activated natural killer (NK) cells (CD56+CD16+CD69+CD158b+) were associated with a significantly lower risk of aGVHD (P = .0016; HR, .51; 95% confidence interval, .33 to .78), whereas late-activated HLA-DR+ CD3+ cells were associated with significantly higher aGVHD (P < .0005; HR, 2.31; 95% confidence interval, 1.55 to 3.43). In a subgroup of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), receipt of an allograft from an older donor (≥40 years) was associated with a higher incidence of relapse (P = .0042; HR, 2.99); allograft content of early activated CD3+ cells (CD3+CD69+; P = .0024; HR, .4) and NKT cells (CD3+CD56+; P = .0006; HR, .54) were associated with a lower incidence of relapse. Presence of HLA-Bw4-80Ile+ genotype was associated with lower relapse incidence. In conclusion, activated NK cells within PBSC allografts associate with lower aGVHD risk, whereas HLA-DR+ T cells associate with higher aGVHD and cGVHD risk. NKT cells and early activated T cells are associated with lower relapse risk in AML and MDS patients. These findings may have implications in therapeutic targeting of select populations in the allograft to minimize incidence of GVHD.

High Predictive Value of Pre Transplant Minimal Residual Disease Assessment By Combining WT1 Expression and Flow Cytometry in Acute Myeloid Leukemia

BACKGROUND AND AIMSAllogeneic bone marrow transplantation (BMT) offers the greatest chance of cure for patients with high-risk acute myeloid leukemia (AML). Persistence of disease or high levels of pre BMT minimal residual disease (MRD) have been reported to predict relapse risk after BMT. WT1 expression levels and multicolor flow cytometry (MFC) are the most common tools to evaluate MRD. We recently reported that combining WT1 expression and MFC for MRD detection after induction therapy strongly impacts on relapse risk in AML. The aim of this study was to analyze the role of pre-BMT MRD assessment as predictor for the post-transplant relapse risk.MATERIALS AND METHODSWe retrospectively analyzed the outcome of 253 consecutive AML patients receiving allo-BMT. Pre-BMT marrow samples were analysed for WT1 expression and MFC as MRD evaluation . Median age at transplant was 45 years. Disease phase was CR1 in 161, CR2 in 63, and CR3 in 29 patients. One hundred eighty-two received myeloablative conditioning, whereas 71 patients received reduced intensity conditioning. Median follow-up was 59 months (95% CI 46.2 - 71.8 months). Relapse-free survival (RFS) was calculated from the time of transplantation until last follow-up or documented leukemic relapse. Overall Survival (OS) was calculated from the time of transplantation until death by any cause or last follow-up.A positive MFC MRD was defined by the presence of no less than 25 clustered leukemic cells/105 total events (threshold of 2.5x10-4 residual leukemic cells) at four-color flow-cytometry. Real-time PCR for WT1 was performed on DNA Engine 2 (Opticon®, MJ Research®). WT1 copy number/Abl copy number 500x104 was used as cut-off value for abnormal WT1 expression.RESULTSRelapse occurred in 81 patients (32%). Three-year estimate of RFS was 63.7% (median not reached). The probability of relapse was significantly affected by disease status (first or subsequent CR, p<0.01), occurrence of acute GVHD (grade 0-1 versus 2 or more, p <0.05), MRD status before transplantation, measured with any method (p <0.001 for WT1-based MRD, p<0.03 for MFC based MRD, p<0.0001 for combined MRD). Multivariate RFS analysis revealed that the combined MRD evaluation was the only independent predictor of RFS (p <0.001).Specifically, MFC-MRD was the strongest predictor of longer relapse free survival (p <0.001) since only two relapses occurred in the 25 MFC-MRD negative patients and 3-years RFS was 89.9%. Among MFC-MRD positive patients, WT1 MRD status stratified the risk of relapse as the 3-years RFS was 71.9% and 31.3%, respectively, for patients with normal or increase WT1, p <0.01, fig.1). The predictive value of MRD was independent from induction schedules, donor type, disease status at BMT and risk group, occurrence of acute or chronic GVHD. Similarly, MRD evaluation was a strong predictor of long term survival, as 3- years OS was 77.2% for MFC negative and 36.9% for double WT1 and MFC MRD positive patients, respectively, (p <0.001). Multivariate OS analysis showed that BMT year, disease status at BMT and combined MRD evaluation significantly influenced OS duration (p <0.001, <0.002 and <0.003, respectively)CONCLUSIONSPre transplant MRD evaluation by WT1 and MFC on bone marrow samples is a reliable predictor of relapse risk. Patients with both negative pre-BMT MRD markers have a significantly longer RFS, while patients with both positive MRD markers display an higher risk of relapse. Identifying patients who have an higher risk of relapse could open the way to apply pre-emptive therapeutic strategies to prevent AML relapse, from donor lymphocyte infusion to other innovative approaches. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Cytomegalovirus Reactivation after Allogeneic Hematopoietic Stem Cell Transplantation is Associated with a Reduced Risk of Relapse in Patients with Acute Myeloid Leukemia Who Survived to Day 100 after Transplantation: The Japan Society for Hematopoietic Cell Transplantation Transplantation-related Complication Working Group

Cytomegalovirus (CMV) infection is a major infectious complication after allogeneic hematopoietic cell transplantation (allo-HSCT). Recently, it was reported that CMV reactivation is associated with a decreased risk of relapse in patients with acute myeloid leukemia (AML). The aim of this study was to evaluate the impact of early CMV reactivation on the incidence of disease relapse after allo-HSCT in a large cohort of patients. The Japan Society for Hematopoietic Cell Transplantation's Transplantation-Related Complication Working Group retrospectively surveyed the database of the Transplant Registry Unified Management Program at the Japan Society for Hematopoietic Cell Transplantation. Patients with AML (n = 1836), acute lymphoblastic leukemia (ALL, n = 911), chronic myeloid leukemia (CML, n = 223), and myelodysplastic syndrome (MDS, n = 569) who underwent their first allo-HSCT from HLA-matched related or unrelated donors between 2000 and 2009 and who survived without disease relapse until day 100 after transplantation were analyzed. Patients who received umbilical cord blood transplantation were not included. Patients underwent surveillance by pp65 antigenemia from the time of engraftment, and the beginning of preemptive therapy was defined as CMV reactivation. Cox proportional hazards models were used to evaluate the risk factors of relapse, nonrelapse, and overall mortality. CMV reactivation and acute/chronic graft-versus-host disease (GVHD) were evaluated as time-dependent covariates. CMV reactivation was associated with a decreased incidence of relapse in patients with AML (20.3% versus 26.4%, P = .027), but not in patients with ALL, CML, or MDS. Among 1836 patients with AML, CMV reactivation occurred in 795 patients (43.3%) at a median of 42 days, and 436 patients (23.7%) relapsed at a median of 221 days after allo-HSCT. Acute GVHD grades II to IV developed in 630 patients (34.3%). By multivariate analysis considering competing risk factors, 3 factors were significantly associated with a decreased risk of AML relapse and 1 factor with an increased risk of AML relapse: CMV reactivation (hazard ratio [HR], .77; 95% confidence interval [CI], .59 to .99), unrelated donor compared with related donor (HR, .59; 95% CI, .42 to .84), development of chronic GVHD (HR, .77; 95% CI, .60 to .99), and pretransplantation advanced disease status compared with standard disease status (HR, 1.99; 95% CI, 1.56 to 2.52). However, CMV reactivation was associated with increased nonrelapse mortality (HR, 1.60; 95% CI, 1.18 to 2.17) and overall mortality (HR, 1.37; 95% CI, 1.11 to 1.69). A beneficial effect of CMV reactivation on subsequent risk of relapse was observed in patients with AML but not in those with other hematological malignancies. However, this benefit was nullified by the increased nonrelapse mortality. The underlying mechanism is unclear; however, immunological activation against CMV reactivation plays an essential role in this association. Thus, immune augmentation treatment options, including vaccination and adoptive T cell transfer, may be useful to take advantage of the efficacy of CMV reactivation with minimal increase in nonrelapse mortality.